Observation of recovery and recrystallization in high-purity aluminum measured with forward modeling analysis of high-energy diffraction microscopy

Observation of annealing twin nucleation at triple lines in nickel during grain growth

“…The three annealing times were 23 min, 30 min, and 25 min. Details of the nf-HEDM experiment and data analysis are given elsewhere [23][24][25][26][27][28].…”

“…For example, serial sectioning cannot be directly applied to this problem because the sample is destroyed during analysis [1,21,22] and transmission electron microscopy can only visualize the structure within very thin, nearly two-dimensional, samples. However, the recent development of near-field high-energy X-ray diffraction microscopy (nf-HEDM) [23][24][25][26][27][28] and X-ray diffraction contrast tomography [29,30] enables non-destructive measurements of the shapes and orientations of grains within a bulk sample at sequential stages during annealing.…”

“…With previously available techniques, it was simply not possible to observe the same triple junction before and after the event. The repetitive non-destructive three-dimensional structural characterization afforded by nf-HEDM [23][24][25][26][27][28] makes it possible to directly observe the boundary replacement mechanism, if it occurs, and to evaluate the grain boundary crystallography and grain boundary dihedral angles. In this paper, results from high purity Ni annealed at 800°C show that twins form at triple lines, as depicted above, and that the process decreases the total interfacial energy.…”

Deformation-induced orientation spread in individual bulk grains of an interstitial-free steel

“…As the technique is nondestructive it enables studies of the same set of bulk grains before and after some external stimuli, e.g. elastic [5][6][7] and plastic deformation [8][9][10][11] or thermal annealing [12][13][14]. Several experimental set-ups are possible, each with specific advantages, e.g.…”

Three-dimensional characterization of microstructurally small fatigue-crack evolution using quantitative fractography combined with post-mortem X-ray tomography and high-energy X-ray diffraction microscopy

“…The experimental geometry implemented at the APS 1-ID beamline for near-field HEDM [41,42] was originated by Poulsen [43]. Combined with forward modeling reconstructions [41,44], the technique yields 3-D maps of crystallographic-orientation variations within and between grains in both ordered [45] and defected [46][47][48] materials. For a given cross-section of the specimen illuminated by the line-focused (approximately 0.004 Â 1.3 mm 2 ) monochromatic (50 keV) X-ray beam, diffraction spots from grains satisfying the Bragg condition were imaged as the sample rotated through 180°about the z axis, with images collected over 1°integration intervals; this procedure was repeated at two rotation-axis-to-detector positions.…”